On Hardness and Electronegativity Equalization in Chemical Reactivity Theory
On Hardness and Electronegativity Equalization in Chemical Reactivity Theory
复制标题
化学反应理论中的硬度与电负性均衡
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
A. Wasserman
中科院分区：
文献类型：
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作者：
M. Cohen;A. Wasserman
化学反应性理论（CRT）包含的反应性指标被定义为基态性质对电子数（如电负性和硬度）的一阶和二阶导数。这就需要使用Perdew， Parr， Levy和Balduz （PPLB）版本的非整数密度泛函理论（NIDFT）来为DFT中的CRT提供基础。然而，PPLB NIDFT产生的基态性质是分段线性连续函数，产生的硬度消失和阶梯电负性不允许电负性均衡。为了克服这些困难，在本文中，我们修改了CRT和DFT之间的关系，前者基于我们之前在“分子”理论（AIMT）中表述的“原子”，但保留了PPLB NIDFT。我们通过一个独特定义的反应电位重新获得电负性平衡。我们证明了可以定义一个正定的硬度矩阵，它控制了系统各部分电子数内部波动的AIMT能量泛函的最小代价。
Chemical Reactivity Theory (CRT) contains reactivity indices defined as first and second derivatives of ground-state properties with respect to electron number such as the electronegativity and the hardness. This necessitates use of the Perdew, Parr, Levy, and Balduz (PPLB) version of noninteger density-functional theory (NIDFT) to provide a basis for CRT in DFT. However, the PPLB NIDFT yields ground-state properties which are piecewise linear continuous functions of number, yielding vanishing hardness and staircase electronegativities which do not admit electronegativity equalization. To overcome these difficulties, in the present paper we modify the relationship between CRT and DFT, basing the former on our previously formulated “atoms” in “molecules” theory (AIMT) but retaining the PPLB NIDFT. We recapture electronegativity equalization through the agency of a uniquely defined reactivity potential. We demonstrate that a positive definite hardness matrix can be defined which controls the minimum cost to the AIMT energy functional of internal fluctuations of the electron numbers of the parts of a system.